Front

The Shimano GRX RX815 Di2 front derailleur delivers quick and smooth front shifting even under high pedaling torque. It's designed for a wider, 17T front chainring range, has programmed chain guide trim settings, and can be used in full or semi Shimano Synchronized Shift modes. - Chainline +2.5 mm vs. conventional road FD - Wide, 17T front range chainring range - Wider tire clearance

Combining Shimano's Di2 platform and the road incarnation of Hyperglide+, the Ultegra FD-R8150 front derailleur shifts between chainrings with the fast and seamless action. - Small, sleek and lightweight front derailleur - Frontal area is smaller than previous designs to reduce aerodynamic drag - Top gear teeth capacity: 50-54t - 61-66 degree chainstay angle - Includes 1 SD300 port

Shimano Ultegra R8050 Di2 front derailleur. - Quick and smooth front shifting under high pedaling torque - Programmed control of chain guide - Shimano Synchronized shift - Full and semi synchronized shifting program - Redesigned to fit wider gear pitch without sacrificing shifting - Shorter length of rear center (410mm) with O.L.D. 135mm - System communication with rear derailleur, Programmed control of chainguide works for minimal chance of chain drop - Top Gear Teeth: 46-53T - Chain Stay Angle: 61-66 - Chain Line: 43.5 - Average Weight: 132 grams